FACTBOX: India's mammoth general election

(Reuters) - The biggest election the world has ever seen begins in India on Monday in two remote backwater states, with the country looking increasingly likely to embrace a coalition led by a Hindu nationalist to jumpstart a flagging economy.

Here key highlights:

- Roughly 814.5 million people are registered to vote, an increase of more than 100 million since the last parliamentary election in 2009. In other words, India has added a population greater than that of the Philipines to its voter rolls in five years.

- Of those, over 23 million are between 18 to 19 years old. A surge in enrollment in this age group means they now constitute 2.88 percent of total voters, against 0.75 percent in 2009.

- Election dates in parliamentary constituencies were set taking into consideration extreme summer heat, monsoon rains, harvest seasons, religious festivals and most importantly, school exams. Most polling stations are placed in schools.

- Voting will be held in nine stages across the country over a period of five weeks. This is to allow police and other security forces to be deployed in strength in areas where polling is held. Counting begins on May 16 and the results are due to be announced on the same day.

- Voters will cast their ballots in about 930,000 polling stations, an increase of nearly 12 percent since 2009.

- For the first time in a general election, voters will have a "None of the Above" option on the ballot papers and electronic voting machines. The option was brought in last year in response to activist groups who said voters were too often forced to choose between several candidates with criminal backgrounds.

- To curb "the abuse of money power" during the elections, "flying squads" and static surveillance teams will guard against the distribution of cash or other bribes to voters. Committees will also keep their eyes peeled for illegal election advertisements and politically funded stories planted in the media.

- The income tax department and the government's financial intelligence unit have been instructed to keep watch on the movement of cash during elections. In previous elections, political operatives were caught driving with suitcases packed with cash in car trunks, ambulances and hearses.

- The Election Commission will monitor production, storage and distribution of liquor during elections. Indian political parties are notorious for handing out alcohol and even prescription medication as bribes to voters.

- Transgender persons can for mark their gender as "Others" on the electoral rolls, a category that did not exist in 2009. 28,314 voters have listed their gender in this way.

- Booth officers will do door-to-door surveys to prepare a list of voters found absent at their home in an effort to prevent impersonation. Dead voters and those who have moved from their homes will be added to a list to check against the rolls to ensure no foul play on voting day.